Retiring Labor MP Alannah MacTiernan says she wasn't satisfied with her role and the difficulty of establishing herself in three short years in Canberra.
She is open to a return to state politics, but ruled out challenging WA Labor leader Mark McGowan for his job.
Ms MacTiernan announced her retirement on Friday night, deciding not to recontest the seat of Perth she won in 2013.
She said the decision was the best thing for her seat.
"Is it really good to keep going if fundamentally you are not satisfied with the role that you have?" Ms MacTiernan told reporters on Saturday.
"I think if I now stand aside, let someone come in that's at the beginning of their political career that has the patience and the time... that is in the best interests of everyone."
Ms MacTiernan said it had been difficult going across from WA without a faction and trying to find her place in the pecking order in Canberra.
She ruled out challenging Mr McGowan for the Labor leadership.
"Mark will be the next premier of Western Australia and I can tell you, I will not be out there contesting him for his job," she said.
"I'll be totally honest, if there is an opportunity for me to serve with Mark, I would not rule that out.
"But I'm telling you, I'm not in the business of destabilising a leader who has been successful, who's worked hard, done the hard yards, is ahead in the polls."
Ms MacTiernan served in state parliament from 1993 to 2010, when she made a failed attempt to unseat Liberal Don Randall in Canning.
